Many articles exist that need to maintain a generally airtight or hermetic seal in order to function properly. It may be desirable to test the integrity of the seal on a regular basis to determine whether the article is to be replaced and/or repaired. According to conventional methods, the article may be immersed in a pressurized gas such as helium, and then placed in a lower pressure environment in which the gas is generally not present. If the gas has been absorbed into the article, it will be released and detected, indicating a faulty seal.
Such methods, and others known in the art, may be expensive and/or difficult to carry out. It may be desirable to engage in periodic testing of the seal integrity of the article, but repeated performance of such testing may multiply the expense and/or inconvenience.
One type of article for which seal integrity testing may be desired is a battery, or more specifically, a lithium-ion battery. Lithium-ion batteries may generally need to maintain a hermetic seal in order to operate properly. Such a seal may be particularly difficult to maintain with the duty cycle involved in aviation, particularly where the battery may be stored in an un-pressurized part of the aircraft. Thus, the battery may be subjected to repeated reduction of ambient pressure as the aircraft ascends to cruising altitude, and a similar increase of ambient pressure as the aircraft once again descends. Such batteries may be important for the operation of the aircraft's electrical systems.
Accordingly, it may be desirable to regularly check the hermetic seal of such batteries. It may be further desirable for the testing method used to be non-destructive so that batteries that have passed the test may be readily re-used. Further, it may be desirable for the testing method to be rapidly and inexpensively carried out. Yet further, it may be desirable for the testing method to be reliable and accurate so that faulty batteries can be easily detected, and repaired and/or replaced.